The present invention relates to a modular tibial implant for use in total knee arthroplasty. More particularly, it relates to a modular tibial implant for use in Minimally Invasive Surgery (MIS) wherein all of the components can be installed through an incision on either the medial side or lateral side or on an anterior-lateral or anterior-medial location on the knee.
In the past, resurfacing of a knee joint was performed with the implantation of prosthetic femoral and tibial components through an incision extending proximally to distally along the anterior surface of the knee adjacent the lateral or medial sides of the patella. This required a comparatively long incision to be made in order to install the prosthetic femoral and tibial components. Recently, there has been progress towards shortening the incision and moving the incision either medially or laterally from the prior art anterior incision. While direct medial or lateral approaches are possible, it is preferred to have an anterior-medial or anterior-lateral approach.
U.S. Patent Publication No. 2003/0171757 relates to such a minimally invasive total knee arthroplasty method and instrumentation used therefor. In addition, co-pending, commonly assigned U.S. application Ser. No. 10/768,520, the disclosure of which is hereby incorporated by reference herein, teaches instrumentation used during minimally invasive procedures.
The size of incisions, while of secondary importance to not everting or subluxing the patella, has been reduced and may be in the range of 7-9 cm. Consequently it has been found necessary to utilize femoral and tibial prosthetic implants, which are adapted to be inserted through this reduced incision. One way of producing such an implant is to make the parts of the implant modular so that they may be inserted into a prepared knee in series. For example, with respect to the tibia, a typical tibial implant includes a stem or a keel, a baseplate and a modular bearing insert typically made of a polymeric material such as ultra-high molecular weight polyethylene.
Modular prosthetic knee components are known and are shown in U.S. Pat. Nos. 5,152,796, 5,326,359, 6,258,127, 6,506,216 , and 5,413,605. These patents relate to methods of attaching modular stems or keels to a femoral or tibial component.
In spite of the above advances, there remains a need for improved modular tibial implants that are safe, reliable, cost effective and easy to implant during a surgical procedure.